The present invention relates to semiconductor devices, and more particularly, to the fabrication and use of novel electronic devices made using conductive polymer materials having nanowires (or other nanostructures) incorporated therein and/or thereon.
The advancement of electronics has been moving towards two extremes in terms of physical scale. Rapid miniaturization of microelectronics according to Moore's law has led to remarkable increases in computing power while at the same time enabling reductions in cost. In parallel, extraordinary progress has been made in the other, relatively less noticed, area of macroelectronics, where electronic devices are integrated over large area substrates with sizes measured in square meters. Current macroelectronics are primarily based on amorphous silicon (a-Si) or polycrystalline silicon (p-Si) thin film transistors (TFTs) on glass, and are finding important applications in areas, including flat panel display (FPD), solar cells, smart cards, radiofrequency identification tags, image sensor arrays and digital x-ray imagers.
While the current technology is successful in many perspectives, it is limited in what applications it can address. For example, there has been growing interest in the use of plastic as the substrate for macroelectronics due to plastic's light weight, flexibility, shock resistance and low cost. However, the fabrication of high performance TFTs on plastics has been extremely challenging because all process steps must be carried out below the glass transition temperature of the plastic. Significant efforts have been devoted to search for new materials (such as organics and organic-inorganic hybrids) or new fabrication strategies suitable for TFTs on plastics, but only with limited success. Organic TFT's promise the potential of roll-to-roll fabrication process on plastic substrates, but with only a limited carrier mobility of about <1 cm2/V·s The limitations posed by materials and/or substrate process temperature (particularly on plastic) lead to low device performance, restricting devices to low-frequency applications. Therefore, applications that require even modest computation, control, or communication functions cannot be addressed by the existing TFT technology.
Individual semiconductor nanowires (NWs) and single walled carbon nanotubes can be used to fabricate nanoscale field effect transistors (FETs) with electronic performance comparable to and in some case exceeding that of the highest-quality single-crystal materials. In particular, carrier mobility of 300 cm2/V·s has been demonstrated for p-Si NWs, 2000-4000 cm2/V·s for n-indium InP NWs and up to 20,000 cm2/V·s for single walled carbon nanotubes. These nanoFETs promise to push Moore's law to the ultimate limit—molecular level—with unprecedented performance. They are, however, currently hard to implement for production-scale nanoelectronics due to the complicated and limited scalability of the device fabrication processes.
What are needed are high performance TFTs that can be applied to plastics and other substrates requiring low process temperatures. What is also needed is a production scalable method for fabrication of nanoscale semiconductor devices than can be used as high performance TFTs on plastics and other substrates requiring low-process temperatures.